I haven't actually done this, but I remember reading about this
technique. As I recall, the instructions I read said to use an
inverted cone bur that just fits into the hole to flare the end of
the hole. Also, you can put two half-round pieces of wire together,
solder at one end, rather than try to saw a piece of round wire.
I think I would skip the flaring part-- the last thing you want is
to have everything go great, get yout wedge pushed in, your pearl
permanently mounted-- and find that the setting is still loose, as
it could be if you flared it too much. If the flared area extends
downward too much, the pearl could move up and down, at least in my
Good luck-- let us know if you try this, and how it goes!